Die blanks and method of making dies



May 12, 1931, F. ofwg aLLs DIE BLANKS AND METHOD 0F MAKING DIES Filed March 3. 1927 I INVENTOR,' iml' Wells,

Patented May 12, 1931 UNITED SATE FRALTK o. WELLS, on GREENFIELID; MASSACHUSETTS DIE lBLANKS AND METHOD OF MAKING DIES Application filed March 3;

' This invention relates to dies, die blanks and methods of making the same.

One object of the invention is to provide an improved process of making thread cut- 6 ting dies which will facilitate the manufacture of such dies, reduce their cost of manufacture and produce a' more uniform and durablelproduct.

Another object is to provide an improved die blank which may be economically manufacturedand which may be readilytransformed by punching, threading and finishilng operations into a finished thread cutting Other objects will be inpart obvious andin-part pointed out hereinafter.

One illustrative die blank and one illustrative die which may be made therefrom are shown in the accompanying drawings, in which: i

Fig. 1 is a top plan view of a die blank embodying the invention.

Fig. 2 is a sectional view taken on vthe line 22 of Fig. 1. I

Fig. 3 is a .top plan view of the die blank after the web portion connecting the ends of the lands has been punched 'out and the ends of'the lands have been reamed.

c Fig. 4 is'a vertical sectional view taken 'on the line 4'l of Fig. 3 and illustrating the finished openingthrough the web.

f Fig. '5 is a top plan view showing in dotted lines the threads which have been out on the ends of the lands. I

Fig. 6 is a vertical sectional'view taken on the line 6-6 of Fig. 5 and showing the threads on the ends of the lands. 7 t

Fig. 7 is a,top plan view illustrating how the lands are relieved. T

Fig. 8 is a top plan View of a two part die made from the blank of Fig. 1.

The die blank selected for illustration and which is particularly well adapted for use in producing the two part die shown in Fig.

v4 8, consists'of two body portions 1 and 2,-

preferably of steel and connected by a thin web 3, preferably of the same material and located centrally of the blank. 'Body portion 1 is provided with lands 7 and 10, and

'50 body portion 2 is provided with lands 8 and .and threading the ends of the lands.

1927. Serial No.-172,s20.

9. The lands of the respective bodyportions are oppositely disposed in spaced relationship and are preferably formed integrally with their respective body portions. Each body portion is preferably depressed between its lands on either side of the web 3 to provide chip receiving recesses 13.

The die blank just described is preferably produced from a steel bar or block by a dropforging operation on a drop-forgingv machine; the forming dies of the drop-forging machinebeing so constructed and arranged as to form the two body portions of the blank with their respective lands and recesses connected by the thin web 3the immediate result of the forging operation being substantially the completed blank shown in Fig. 1.

To produce a complete thread cutting die from the die blank of Fig. 1, the blank is subjected to a series of operations now to be described. p i When. the blank comes from the drop forging machine, its outer surfaces are preferably ground or'finished in the usual way. The center of the web 3 which lies between the ends of the-lands 7, .8, 9 and 10, is then removed, preferably'by a punching operation, to provide an opening 6 for reaminlg reamerlis then inserted into the opening 6 .and theends of'the lands are reamed out to provide the desired spaced relationship of the opposed'ends. .The ends of the lands are then provided with cutting threads 11,

preferably by means of a die hob having threaded flutes, which will accurately center itself 'in the reamed opening and form threads of uniform depth on the ends of the lands 7, 8, 9 and 10.

Following the threading operation, the upper and lower edges of the lands are preferably, relieved as at. 12, to provide suitable clearance back of the cutting threads.

' Suitable identifying and size numbers maybe stamped on the respective body por tions 1 and 2.

I To provide a two piece. diesuch as is shown in Fig. 8, the body portions 1 and 2, with their respective lands and recesses, are

separated by removing the remaining portions of the web 3, preferably by punching out such portions.

Either in the forging or finishing operation the side edges of the die may be angled as indicated at 5 in Fig. 2 to permit the die to bereversedin the collet.

The completed dies are usually hardened and tempered.

Among other advantages, the invention produces a better the at .a considerable isaving in the cost of manufacture. Heretofore thread cutting dies have been produced from a bar or block of steel by expensive milling or drilling operations, or from a die blank of such character as to require subsequent expensive milling -or drilling operations. Applicants process, on the other hand, produces by an inexpensive drop forg i-ng' operation, ,;a die blank having lands formedthereon and connected by a thin web of metal, which web may be subsequently removed by an inexpensive punching opera tion, thus eliminating entirely the expensive drilling operation of the prior art.

It is well known that in .a cross-section .of abar of steel thecenter of the bar is of poorer quality and less durable than the outer portions of the bar. When the lands of the die are formed by a drilling operation .at the center of the bar, the poor quality of the material impairs the wearing qualities of the threads. Applicants process of forging a die blank with formed lands compresses .and hardens the material forming the lands, thus refining the material of the lands and rendering it more durable for subsequent thread cutting operations.

.The formation of the lands .and the chip- 'receiving recesses in the. forging operation results in a saving of material and labor.

The invention is particularly advantageousin the manufacture of the two piece die shown in Fig. 8. Heretofore the lands of a two'pieceidie have been produced by a drillingoperation, with the result that there is a more or less lack of uniformity in the dimensions and spaced relationship of the lands. Forging the lands andmaintaining the two parts of the die zin'fixed relationship during the punching, reaming and threading operations results in an accuracy and uniformity .in the lands which are difficult to attain by prior methods.

' It willbe understoodthat the invention is not to be limited to the particular embodiment thereof shown for purposes of illustration and that all of the features of the invention need not be used conjointly, as

, the .'invention may .be variously embodied and the inventive features thereof may be used in different combinations and sub'combinations, as defined in the sub-joined claims.

What I ClaiI n is:" V 1, The method of simultaneously formthreads .on the lands and relieving the threads, next removing the thin web to separate the dies, then hardening and temper- 5. Steps in the method of forming thread cutting dies which consist in first forging a blank to produce oppositely located recesses and lands which are connected together witha web, then removing the cenmoving-the remaining portions of the connecting web for separating the dies.

3. Steps-in the method of forming two part dies which consist in first forging a blank'toproduce recesses and lands on its opposite sides, then forming an 0 ing .in that part of the web whichis ad acent the lands,then insertinga die hob in the opening and forming threads on thelands, then separating the dies by removing the remaining web which connects the dies.

4. Steps in the method of forming two part dies which consist in first forging a blank to produce recesses and lands on its opposite sides, then forming an opening in that part ofthe web which ,is .-ad acent the lands, then inserting a-die hob in the opening and forming threads on'the lands, then separating the diesbyiremoving the remaining web which connectsthe,dies,then hard= threads on the lands, and removingthe remaining portions of the web to provide atwo piece die.

6. The method of makingthread cutting dies which is characterizedv by forging .a die blank having, two body portions provided with oppositely disposed recessesand lands and connected by a-thin web, removing that portion of the web which lies between the endsof the lands, forming threads on the lands, and removing the remaining portion ,of the web to provide a two piece die.

' 7. The method of making thread cutting dies which is characterized by forging a die blank from a block of metal to produce as the immediate result of the forging operation a die blank having a plurality of lands connected at their ends by a thin web of metal, removing. the web between the ends of the lands, and forming threads on the lands.

8. The method of making thread cutting dies which is characterized by forging a die blank from a block of metal to produce as the immediate result of the forging operation a die blank having a plurality of lands connected at their ends by a thin web of metal and oppositely disposed recesses connected by a thin web of metal, removing the web between the ends of the lands, forming threads on the lands, and removing the web between the recesses.

9. As an article of manufacture, a forged metal blank for use in making thread cutting dies, comprising a body portion, and a plurality of lands formed within the body portion'and connected at their ends by a thin web of metal; whereby a punching operation will remove the web from between the ends of the lands and permit the finishing and threading of said ends.

10. As an articleof manufacture, a forged metal blank for use in making thread cutting dies, comprising a two part body, each part being provided with formed lands and the two parts being connected by a thin web of metal; whereby punching, threading and finishing operations will complete the formation of a two piece die.

11. The method of making thread cutting dies which is characterized by forging a die blank having a plurality of body portions provided with lands and connected by a thin web, removing that portion of the web which lies between the ends of the lands, forming threads on the lands, and removing the remaining portion of the web to provide a multiple piece die.

12. The method of making thread cutting dies which is characterized by forging a die blank from a block of metal to produce as the immediate result of the forging operation a die blank having land forming mate rial located centrally of the blank and a plurality of recesses oppositely disposed on either face of the blank and positioned adjacent and around the land forming material and separated by a thin web of metal, forming cutting threads in the land forming material, and removing the web which separates the recesses.

13. As an article of manufacture, a forged A metal blank for use in making thread cutting dies comprising a body portion, land forming material located centrally therein, and a plurality of recesses oppositely disposed on either face of the blank and positioned adjacent to and around the land forming material and separated by a thin 

